The present invention relates organopolysiloxane graft epoxy resins and a method for the preparation thereof.
Epoxy resins modified with an organopolysiloxane are well known in the art. For example, a composition containing a diorganopolysiloxane, both ends of which are modified with an amino group, along with an epoxy resin, is described in Japanese Patent Publication No. 56-8849 [8,849/81]. In said composition, said diorganopolysiloxane modified with amino groups and the epoxy resin undergo a reaction at the time of curing the epoxy resin, and the moisture resistance of the epoxy resin is said to be improved.
Also, in Japanese Patent Publication No. 61-48544 [48,544/86], a composition comprising a block copolymer of a diorganopolysiloxane, both ends of which are modified with amino groups, and an epoxy resin, is disclosed. The block copolymer is believed to be an effective additive for improvement in the cracking resistance of curable epoxy resins.
However, all of these epoxy resins modified with an organopolysiloxane are block copolymers of an organopolysiloxane and an epoxy resin. Therefore, the characteristics of the organopolysiloxane, for example, the water repellency, surface lubricity, and release properties are not adequately exhibited in some cases, and it was not possible to use them in some applications. Therefore, recently, graft-type organopolysiloxane copolymers have gained special attention. For example, an organopolysiloxane-grafted polyurethane resin is disclosed in Japanese Patent Application Laid-Open [Kokai or Unexamined] No. 2-616, and a dimethylpolysiloxane-grafted polyacrylate resin is disclosed in Japanese Patent Application Laid-Open [Kokai or Unexamined] No. 64-1772 [1772/89].